A satellite TV system 50 is described with reference to FIGS. 1A, 1B, and 2. The satellite TV system 50 includes an outdoor unit 49, which includes a satellite dish 52 and an associated low-noise block downconverter (LNB) 54. The LNB 54 receives satellite multimedia or generic data signals, such as video data signals, comprised of a block of frequencies collected by the satellite dish 52, amplifies it, and downconverts the block of frequencies to a lower block of intermediate frequencies (IF). The LNB 54 sends the downconverted data signals to a set top box 58, in other words an integrated receiver decoder, via coaxial connection 100, which serves to demodulate the downconverted video data signals for display by a television 60 or for storage in a storage device. In practice satellite TV system may have multiple dishes and various types of LNBs connected through a cascade of switchers, multi-switches, etc. These Digital Satellite Equipment (DSE) along with other Pieces of intelligent satellite peripheral slave equipment may be connected to the coaxial connection 100. Each of these devices may have to respond to DiSEqC commands issued by the master (integrated receiver decoder i.e., a set top box). Each of these digital satellite equipment (DSE), or stated another way, Satellite Peripheral equipment (SPE) may include a transceiver-controller circuit 56. It is also possible for multiple collocated SPEs to share the transceiver-controller. One such SPE 48 which may be present in a installation is shown in FIG. 1A
The transceiver-Controller circuitry 56 is also coupled to the coaxial connection 100. The outdoor circuitry 56 includes a DC/DC converter 57 (FIG. 2) that receives a power signal over the coaxial connection 100, and converts the received power signal from the set top box (STB) 58 for use by microcontroller (MCU) 108. Traditionally 13V or 18V is sent over the coaxial connection depending on a desired polarization to be selected by the LNB 54 for a signal received by the satellite dish 52 and LNB 54. Some schemes use a fixed voltage such as 12V and rely on a DiSEqC message for selection of polarization. In some cases, some or all of the equipment may be self-powered instead of receiving power over the coaxial connection 100.
A Digital Satellite Equipment Control (DiSEqC) transceiver 55 functions in conjunction with the MCU 108 to permit the MCU 108 to receive commands, responses, or queries over the coaxial connection 100 transmitted using the DiSEqC standard, from set top box 58, and to permit the MCU 108 to transmit commands, queries, or responses over the coaxial connection 100
While existing DiSEqC transceiver 55 designs permit such bidirectional communication, drawbacks persist. For example, DiSEqC signals transmitted by the transceiver 55 may take the form of a trapezoidal or truncated triangular wave, making detection by the LNB 54 or set top box 58 more difficult, and consuming an undesirable amount of power or producing noise. Also, existing DiSEqC transceiver 55 designs may lack a desired degree of adaptability, calibration, and programmability.
Therefore, further development of such DiSEqC transceivers 55 is needed.